Hi!
I'm new on this forum.
I've built a tube mic with the Gyraf G7 schematic. I use an Peluso CEK12 capsule and the Lundahl trafo and a Mullard EF86. The mic works. No buzz or low freq disturbance of any kind. But the S/N ratio is weird. I get a lot of background noise. Sounds like a distant waterfall in the background. My voice comes through loud and clear but the noise in the background is really audiable.
Lot of volume out of the mic. I don't have to turn the gain up very far on my pre-amp to get a good strong signal.
The B+ is 160V from the PSU without the mic and drops to 115 whith the mic connected. Could there be something there...? A bad cap or connection. A bad tube? (even though it seems to work fine) Where to look?
I'm very greatful for any help I can get.
/Anders
I'm new on this forum.
I've built a tube mic with the Gyraf G7 schematic. I use an Peluso CEK12 capsule and the Lundahl trafo and a Mullard EF86. The mic works. No buzz or low freq disturbance of any kind. But the S/N ratio is weird. I get a lot of background noise. Sounds like a distant waterfall in the background. My voice comes through loud and clear but the noise in the background is really audiable.
Lot of volume out of the mic. I don't have to turn the gain up very far on my pre-amp to get a good strong signal.
The B+ is 160V from the PSU without the mic and drops to 115 whith the mic connected. Could there be something there...? A bad cap or connection. A bad tube? (even though it seems to work fine) Where to look?
I'm very greatful for any help I can get.
/Anders